Eve is a bored, whip-smart, pay-grade MI5 security officer whose desk-bound job doesn't fulfill her fantasies of being a spy. Villanelle is a mercurial, talented killer who clings to the luxuries her violent job affords her. Everything changes when they cross paths.

Villanelle has disappeared, and Eve is left reeling, having no idea if the woman she stabbed is alive or dead. With both of them in deep trouble, Eve has to find Villanelle before someone else does. But unfortunately, she's not the only person looking for her.

After the emotional climax of Season Three, Eve, Villanelle and Carolyn are in very different places. Following Eve and Villanelle’s exchange on the bridge, Eve is on a revenge mission, while Villanelle has found a brand-new community in an attempt to prove she’s not a “monster.” Having killed Paul, Carolyn goes to extraordinary lengths to continue to chase down The Twelve and the person that ordered Kenny’s hit. This season follows our extraordinary women, each driven by passion, revenge and obsession, building towards a messy, nuanced and totally glorious series finale.